The invention relates to an apparatus for detecting and locating sources of fire or gas impurities in one or more chambers under surveillance, with a (main) detector for detecting a fire, to which detector a constant portion of the air contained in each chamber under surveillance is directed by means of a suction unit, the air travelling along a pipe which is provided in each chamber under surveillance and which has suction openings, as well as a process for the individual recognition of fires or gas pollution in one or more chambers under surveillance, utilizing a (main) detector, which is connected along a pipe and through suction openings on the pipe with the chamber under surveillance, to enable the continual withdrawal and assessment of gaseous test samples from the chamber under surveillance.
Processes and apparatuses of the kind under discussion are known in the prior art and have developed to the point where, for example, in large halls, high shelving, double flooring or office chambers, the locating of a fire source can present extreme difficulties for fire-fighters. A single smoke suction system with a single fire-detecting unit—depending upon local requirements—may monitor a region up to 2000 m2, which can include a number of rooms. In order to permit fire fighters to quickly locate the alarm position, requirements have been laid down; for example in Germany there is the “Guide for Automatic Fire Reporting Installations, Planning and Construction” (VDS 2095). According to this publication, several rooms can be grouped together into a reporting region, only if the rooms are neighbouring rooms, their access can be easily taken in at a glance, the total surface area does not exceed 1000 m2, and also at the fire reporting central station there are clearly visible optical alarm indicators which, in the event of a fire alarm, can identify the room where the fire is located. In Great Britain the requirements are set forth in Norm BS 5839 “Fire Detection and Alarm Systems for Buildings, part 1—code of practice for system design, installation and servicing”. According to these rules, the reporting area of a single surveyed zone must not exceed 2000 m2. Further detailed stipulations are given for the searching distance, which for the optical recognition by fire-fighters of a fire source within a zone, may not exceed 30 m. As a possible aid to detection, it is recommended to include alarm lamps at various locations.
When herein the term “Brandkenngrosse” (characteristic fire quantity) is used, it is to be understood in terms of physical measurements which underlie measureable alterations in the vicinity of a break-out fire, for example the local temperature, the atmospheric content of solid materials, liquid materials or gaseous materials (the creation of smoke particles or aerosols, or steam), or the local radiation.
In FR 2 670 010 A1 reporting boxes are disclosed which serve to identify the smoke-sucking joint in a branched suction pipe system. This reporting box consists of a point-formed smoke detector built into a housing with cable threading for the connection of the incoming and outgoing pipes, and a signal light on its cover. A disadvantage of this construction is that these signal boxes cannot be supplied at every single suction opening, because of their size, their constructional form and their price.
WO 00/68909 discloses a process and an apparatus for detecting fires in chambers under surveillance, by means of which can be located the source of a fire or of pollution of a gas mixture enclosed by the surveillance space. To this end, the process and the corresponding apparatus utilize, in each space under surveillance, two pipes which there cross each other, and by means of which, using one or more fans, a constant fraction of the air in the chamber under surveillance or in the gas mixture is withdrawn through such an opening provided in the pipes, and is conveyed to at least one detector per pipe for recognizing a fire source or a source of gas pollution. This achieves the location of the fire source or of the pollution source, by consulting both of the detectors with respect to the crossed pipes. Several rooms are under surveillance through pipes arranged in the manner of a matrix with rows and columns, and if need be each with a collection detector for the row and column configuration. A disadvantage of this known apparatus lies in the very substantial installation outlay for the matrix pipe system.
The German Patent DE 3 237 021 C2 discloses a selective gas/smoke detector system with a number of separate suction conduits which are connected at various measurement positions in a room under surveillance, in order to withdraw air or gas samples at these measurement positions. In this arrangement, a gas or smoke detector, in communication with these conduits, reacts to the presence of a particular gas in the probe if a defined threshold value is exceeded, and produces a detection signal which controls an indicator or an alarm switch. Also on the individual suction conduits are arranged closure valves which, by a control loop, are cyclically and periodically controlled. The recognition of a fire using this gas/smoke detection system takes place as follows: the control unit, in the absence of a detection signal, adjusts the closure valves such that all suction conduits are simultaneously in open connection with the detector, and upon receipt of a detection signal switch over to a scanning sequence, by which the suction conduits, usually one after the other, or in groups, are brought into connection with the detector. This functioning for the recognition of a fire source requires above all that the detector, by way of individual and selectively openable conduits, be capable of being brought into connection with the various spaces under surveillance individually. Of necessity, this requires the installation of an extensive conduit system, in order to create these individually selectable connections. A disadvantage of this system is the very high installation cost for the necessary conduits.
Disclosed in International Patent Application WO 93/23736 is an air pollution/smoke recognition apparatus based on a network suction system with a large number of sampling locations at which a gas is removed from the individual room under surveillance. This air pollution/smoke recognition apparatus has control of a number of inlet openings which are connected to the grid-like suction system, and are individually monitored. Under normal circumstances, all of these inlets are open, until the recognition apparatus recognizes polluted air or smoke. By the selective closing of inlet openings it is a simple matter to recognize and determine the boundaries of the fire zone. However, the functioning of this recognition apparatus also requires an extensive installation of suction conduit which must provide a grid-like structure in order to ensure a reliable recognition of a fire source. Here as well, a disadvantage of this known appratus lies in the high cost of installing the conduit system.